The solution of the severe technical and economical problem caused by marine fouling organisms, e.g. barnacles, blue mussels, algae and hydroids, for the shipping industry and in aquaculture has been the use of TBTO (tri-n-butyl tin oxide), copper oxide and herbicides in marine coatings. However, several of these have been recognised to be toxic against non-fouling marine organisms. For example, TBTO has been ascribed effects such as reproduction failure and decrease in adult growth in oysters and the development of imposex in gastropodes such as the dog whelk. Because of these unwanted side effects, the use of TBTO will be stopped by future bans; the International Marine Organisation will recommend a global ban from the year 2005. Therefore it is urgent to find new non-toxic alternatives which exert a specific action on target organisms and which also are biodegradable.
Craik et al in WO 01/27147 discloses a novel cyclic molecular framework comprising i.a. so called cyclotides, i.e. cyclic peptides. These compounds are claimed to be usable for treatment or prophylaxis of disease conditions in animals, mammals and plants.
WO 00/68265 (Ouelette et al) discloses pharmaceutical compounds based on cyclic peptides.
WO 99/21879 (Chang et al) discloses cyclic peptides having antimicrobial and antibacterial activity.